Fast scanning is becoming very important in gas chromatography (GC) and mass spectroscopy (MS) where fast chromatography is reducing run time and improving productivity. Mass spectrometers need to keep up. The market wants instruments that can acquire more than 50 spectra/s over 200 amu.
Currently, quadrupole mass spectrometers scan in one direction. Some instruments scan from low mass to high mass. Others scan from high mass to low mass. Neither offers a significant advantage over the other. FIG. 1 shows a forward scan for a prior art mass spectrometer.
In prior art scanning techniques, the inter-scan delay time, the time between scans includes settling time and backsteps. Settling time is the time required to get the RF and DC rod driver outputs back to the starting point. Backsteps allow the linear control system of the RF and DC time to start tracking the setpoint.